SEARCH · Engineering Papers

Results for “INTERCHANGEABILITY”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 829 records · Page 46

All sources NASA NTRS DOE OSTI

NASA NTRS1980

Primary energy release

The physical processes by which the magnetic energy of a solar active region is converted to other forms of energy in the appearance of a solar flare are discussed. Observations of the secondary manifestations of flare energy release, such as thermal plasmas and energetic particle emissions, are presented, with particular attention given to the temporal variations of flare radiation, the various forms of energy release, flare energy density, flare locations and sizes, energy distributions and H alpha, hard X-ray and microwave burst events. Current models of the primary energy release process are surveyed, and the models of Spicer (1976, 1977), which explains rapid flare energy release in terms of multiple tearing modes causing reconnection in sheared magnetic fields, and Uchida and Sakurai (1976, 1978), which attributes primary energy release to dynamic collapse caused by the interchange instability of the neutral sheet, are examined in detail.

Kahler, S.↗

NASA NTRS1982

Precise Restraightening of Bent Studs

Special tool quickly bends studs back into shape accurately and safely by force applied by hydraulic ram, with deflection being measured by dial indicator. Ram and indicator can be interchanged for straightening in reverse direction.

Boardman, R. E.↗

NASA NTRS1980

Space Transportation System solid rocket booster thrust vector control system

The Solid Rocket Booster, Thrust Vector Control (TVC) system was designed in accordance with the following requirements: self-contained power supply, failsafe operation, 20 flight uses after exposure to seawater landings, optimized cost, and component interchangeability. Trade studies were performed which led to the selection of a recirculating hydraulic system powered by Auxiliary Power Units (APU) which drive the hydraulic actuators and gimbal the solid rocket motor nozzle. Other approaches for the system design were studied in arriving at the recirculating hydraulic system powered by an APU. These systems must withstand the imposed environment and be usable for a minimum of 20 Space Transportation System flights with a minimum of refurbishment. The TVC system completed the required qualification and verification tests and is certified for the intended application. Substantiation data include analytical and test data.

Verble, A. J., Jr.↗

NASA NTRS1980

Wind-tunnel test of an articulated helicopter rotor model with several tip shapes

Six interchangeable tip shapes were tested: a square (baseline) tip, an ogee tip, a subwing tip, a swept tip, a winglet tip, and a short ogee tip. In hover at the lower rotational speeds the swept, ogee, and short ogee tips had about the same torque coefficient, and the subwing and winglet tips had a larger torque coefficient than the baseline square tip blades. The ogee and swept tip blades required less torque coefficient at lower rotational speeds and roughly equivalent torque coefficient at higher rotational speeds compared with the baseline square tip blades in forward flight. The short ogee tip required higher torque coefficient at higher lift coefficients than the baseline square tip blade in the forward flight test condition.

Berry, J. D.↗

NASA NTRS1980

Low cost cryostat

A cryostat for use in a low or a substantially gravity-free environment adapted to cool an experiment through the use of helium 2, or helium in its super fluid state is characterized by a number of interchangeable daughter dewars and helium supply or mother dewar. A low pressure venting system is provided for converting helium contained in the mother dewar to a superfluid state for use as a primary cryogen. Each daughter dewar is adapted to be removably mounted in mated relation on the mother dewar and is characterized by support for an experiment package, a source of helium to be employed as a secondary cryogen. A heat pipe is suspended from each daughter dewar and adapted to be extended into the mother dewar for facilitating cooling of the secondary cryogen. A transfer of heat from the package to the primary cryogen, via the secondary cryogen, is accommodated as a film flow of helium 2 progresses from the heat pipe to the experiment dewar.

Stephens, J. B.↗

NASA NTRS1980

An experimental study of the effects of swirl and density difference on mixing in shear flow

Experiments were carried out on the mixing of streams with and without swirl and with and without density differences in a coannular geometry. Three variations of flow visualization techniques were used: direct excitation, collisional excitation, and quenching of the tracer. The axial variation of the flow for the case with swirl in the inner annulus is investigated in some detail. From the flow visualization pictures, it is concluded that the initial Helmholtz instability of the tangential shear layer gives rise to small scale peripheral strucutres, then it is possible that the inner swirling stream drives an instability which turns these small scale peripheral structures into ones of larger scale, thereby rearranging the initial vorticity distribution of the flow field. The pictures also indicate the occurrence of interchange of fluid between the annuli. It is also concluded that the interaction of density field with the resulting radial pressure gradient may have influenced the evolution of the flow structures.

Tan, C. S.↗

NASA NTRS1980

Shuttle orbiter Ku-band radar/communications system design evaluation

Tasks performed in an examination and critique of a Ku-band radar communications system for the shuttle orbiter are reported. Topics cover: (1) Ku-band high gain antenna/widebeam horn design evaluation; (2) evaluation of the Ku-band SPA and EA-1 LRU software; (3) system test evaluation; (4) critical design review and development test evaluation; (5) Ku-band bent pipe channel performance evaluation; (6) Ku-band LRU interchangeability analysis; and (7) deliverable test equipment evaluation. Where discrepancies were found, modifications and improvements to the Ku-band system and the associated test procedures are suggested.

Dodds, J.↗

NASA NTRS1981

The 15th Aerospace Mechanisms Symposium

The purpose of the symposium was to provide a forum for the interchange of information among those active in the field of mechanism technology. To that end, 27 papers were presented on aeronautics and space flight, with special emphasis on actuators and aerospace applications for pointing systems, latches, connectors, and other mechanisms for large space structures. The papers were authored by engineers from a broad aerospace spectrum including the U. S. aerospace industry, NASA, and several European participants. Technological areas covered include: aerospace propulsion; aerodynamic devices; crew safety; space vehicle control; spacecraft deployment, positioning, and pointing; deployable antennas/reflectors; and large space structures. Devices for payload deployment, payload retention, and crew extravehicular activities on the space shuttle orbiter are also described.

Actuators↗

NASA NTRS1981

Behavior of aircraft antiskid braking systems on dry and wet runway surfaces: Hydromechanically controlled system

The investigation utilized one main gear wheel, brake, and tire assembly of a McDonnell Douglas DC-9 series 10 airplane. The landing-gear strut was replaced by a dynamometer. During maximum braking, average braking behavior indexes based upon brake pressure, brake torque, and drag-force friction coefficient developed by the antiskid system were generally higher on dry surfaces than on wet surfaces. The three braking behavior indexes gave similar results but should not be used interchangeably as a measure of the braking of this antiskid sytem. During the transition from a dry to a flooded surface under heavy braking, the wheel entered into a deep skid but the antiskid system reacted quickly by reducing brake pressure and performed normally during the remainder of the run on the flooded surface. The brake-pressure recovery following transition from a flooded to a dry surface was shown to be a function of the antiskid modulating orifice.

Tanner, J. A.↗

NASA NTRS1981

Slide Release Device

A prototype release mechanism is discussed which is interchangeable with the existing orbiter/external tank separation bolt and offers reduced weight, shock, and cost. The components are reuseable. The unit takes maximum advantage of the shank diameter and installs in the monoball just as does the shear bolt, by threading in the completely assembled condition. Actuation is different, in that instead of axially breaking the shank by very high pressure (on the order of 60,000 psi) using a very large force (over 235, 000 pounds), this mechanism releases the shank by cross-axis movement against a lubricated surface. Once free, the shank is driven out of the monoball by an axially precompressed spring. Final weight can be as low as 30 pounds, and the cartridge contains less than one gram of powder. The components show no significant wear after eleven actuations under load.

Source record↗

NASA NTRS1981

Payload carrier systems for conducting sortie mode science

The capabilities and characteristics of the payload carriers developed to provide structural and operational interfaces between the Space Shuttle and the various types of experiments designed to operate in the sortie mode are discussed. The Spacelab is a flexible laboratory system composed of interchangeable elements that can be put together in eight different combinations of pallets and pressurized modules, and provides considerable standard services to users in such areas as equipment installation, power distribution, thermal control, command and data management, software, pointing systems and crew participation. A modular three-axis pointing control system designated the Annular Suspension and Pointing System, is being developed to provide additional pointing capabilities to those payloads that require capabilities not provided by the Spacelab instrument pointing system. Two engineering models of the Spacelab pallet have been designated Orbital Flight Test Pallets which, together with a special experiment support structure, are intended for initial and operational payloads that do not constitute a complete Spacelab mission. The simplest and smallest payload carriers are the Getaway Special cans, intended for small, self-contained, self-sufficient payloads, and the orbiter middeck lockers. In this way, most of the user requirements for Shuttle sortie missions identified to date can be fulfilled.

Jean, O. C.↗

NASA NTRS1980

Applications of Spacelab Payload Standard Modular Electronics /SPSME/

The NASA sponsored Spacelab Payload Standard Modular Electronics program has been designed with the basic objective of providing a space-qualified set of standardized modular electronics to support investigations identified for Spacelab payloads. These units are reusable, have functional, physical, and interface characteristics which allow them to be conveniently assembled in a multitude of configurations, and functionally interchangeable with their ground-based equivalents. The interfacing and control modules are described and typical hardware applications are presented.

Wilkinson, D. D.↗

NASA NTRS1980

HiMAT systems development results and projections

Significant findings of the Highly Maneuverable Aircraft Technology Remotely Piloted Research Vehicle (HiMAT RPRV) flight test program are presented. Among the topics covered are: aerodynamic scaling relationships, the aeroelastic tailoring of wing and canard twist and camber, and laminate graphite/epoxy composite primary structure performance under high-g loading maneuvers. Attention is also given to the set of actuators used in the test and development program, with a view to the minimization of costs through modularity and interchangeability of components and the extensive use of off-the-shelf equipment. The relationship between composite ply geometry and the shape and magnitude of aeroelastic deformations during maneuvering is discussed in detail.

Brown, L. E., Jr.↗

NASA NTRS1980

Advanced X-ray Astrophysics Facility /AXAF/

The Advanced X-ray Astrophysics Facility (AXAF) will be a national observatory designed for the observation of galactic and extragalactic X-ray sources. The observatory is currently planned to be launched by the Space Shuttle, maintainable in orbit and retrievable, if necessary, during its 10 to 15 years of operation. The heart of the AXAF is an X-ray telescope made up of six Wolter type 1 mirrors, with the diameter of the outermost mirror 1.2 m. The focal length will be 10 m, and the AXAF will allow for interchanging and (in-orbit) replacing of focal plane instruments. The optics are being designed to provide a spatial resolution of 0.5 arc second over a several arc-minute field and somewhat reduced angular resolution over the entire 1-degree field of view. The energy bandwidth will be 0.1 to 8 keV. These design goals place severe requirements on the materials, tolerances, construction, and alignment of the telescope. These will be discussed and compared to previous work in this area.

Weisskopf, M. C.↗

NASA NTRS1981

Performance analysis of SA-3 missile second stage

One SA-3 missile was disassembled. The constituents of the second stage were thoroughly investigated for geometrical details. The second stage slotted composite propellant grain was subjected to mechanical properties testing, physiochemical analyses, and burning rate measurements at different conditions. To determine the propellant performance parameters, the slotted composite propellant grain was machined into a set of small-size tubular grains. These grains were fired in a small size rocket motor with a set of interchangeable nozzles with different throat diameters. The firings were carried out at three different conditions. The data from test motor firings, physiochemical properties of the propellant, burning rate measurement results and geometrical details of the second stage motor, were used as input data in a computer program to compute the internal ballistic characteristics of the second stage.

Helmy, A. M.↗

NASA NTRS1981

Numerical modeling of diffusive-convective physical vapor transport in cylindrical vertical ampoules

Diffusive-convective physical vapor transport (PVT) in cylindrical, vertical ampoules of aspect ratio (length/radius) between 0.5 and 10 was modeled numerically. The transport of a crystal forming component through an inert component that undergoes zero net transport was considered. Systems were treated in which: (1) with unequal molecular weight of the components and with temperature gradients typically employed in PVT, convective flow arises dominantly from solutal density gradients; and (2) with equal molecular weight of the components, convective flow can arise only from thermal expansion. It was found that, due to the diffusion-induced horizontal density gradients, buoyancy-driven convective flows are superimposed on the diffusive-advective fluxes without threshold. Net recirculation sets in adjacent to the growing interface, in contrast to the corresponding monocomponent situation where marginally stable convective modes fill the whole fluid space. Depending on the orientation of the main transport direction with respect to gravity, convection can either reduce or enhance the diffusion-induced radial concentration gradients. Significant enhancement of the net transport rate was found to occur only when the whole vapor space between source and growing crystal is filled by a convective recirculation roll. Solutal and thermal convection results are similar; yet for quantitative discussions, thermal and solutal Rayleigh numbers are not interchangeable in contrast to convective situations that lack net mass transport across the fluid space.

Markham, B. L.↗

NASA NTRS1981

Delta's role in reaching the fourth environment

The Delta launch vehicle has played a significant role in spaceand airborne studies since its first launch in 1960, and a high volume period of service is planned for the 1980s. The historical role played by Delta in launching satellites from 1960 to the present is discussed, and vehicle modifications made during this period are summarized. It is shown that out of 154 launches, 143 proved successful for an overall reliability of 93%. The forecasted launch schedule through 1985 is also presented. Various modifications are now under way to provide spacecraft interchangeability with the Shuttle: a Payload Assist Module (PAM) is proposed to provide an orderly transition from the Delta expendable vehicle to the Shuttle reusable vehicle; the new Delta 3920 Improved Second Stage is the result of a need for improved Delta performance to meet 3910 payload capabilities; the firing sequence of the solid rocket motors was altered from five at liftoff and four during ascent to a sequence of six and three, thereby increasing spacecraft weight in geosynchronous transfer orbit. Potential future improvements discussed include the Delta 4920, 9-ft-diam fairing, booster engine performance, PAM solid motor performance, a universal second stage, a hydrogen-oxygen second stage, and large strap-on solids.

Grimes, D. W.↗

NASA NTRS1983

Device Makes Handtools "Dropproof"

Interchangeable-socket dropproof wrench comprises three essential parts: handle assembly, socket assembly, and pip-pin assembly. Socket assembly is disengaged from handle assembly only when engaged to pip-pin assembly. Socket assembly therefore remains tethered and cannot be dropped or lost except by deliberate removal of pip-pin. Dropproof tool is useful where ever loss of component would be inconvenient or hazardous. Used by divers and by people working on scaffolds. Mechanism is easily operated by Technicians wearing thick gloves, space suits, diving suits, or other protective attire.

Mccandless, B., II↗